Self-balancing kite



June 21 1927.

C. DAHL SELFVBALANCING, KITE Filed July 17, 1926 jnfefzzor.

Patented June 21, 1927.

UNITED STATES PATENT OFFICE. I

CONRAD DAHL, OF SPRINGFIELD, OHIO, ASSIGNOR TO ROBERT N. BURTON, OF

CHICAGO,

ILLINOIS.

SELF-BALAN CING KITE.

Application filed July 1'2,

The purpose of this invention is to provide a kite of relatively, simple and economical construction in which the parts are connected together with sufficient flexibilty to permit an automatic adjustment. to the wind pressure upon them for maintaining a proper balance so that the kite will fly steadily and without the use of a tail or other ballast. The invention consistsof certain features and elements of construction in combination, and herein shown and described, and as indicated by the claims.

In the drawing:

Figure 1 is a bottom plan View of a kite embodying this invention.

Figure 2 is a perspective view of the kite in the position which it assumes in flight. Figure 3 is a perspective view with portions of the sailsand other parts broken away "for the purpose of revealing certain details of the frame construction.

Figure 4 is a plan view similar to Figure 1 showing a modified formof the invention. Figure 5 is a detail view looking directly at the lower end of the midrib.

As shown in the drawings this kite comprises a head sail land a main sail 2 which are supported upon two framemembers, a midrib 3 and a cross arm 1. The head sail 1 is in the form of an isosceles triangle hav- 1 ing the opposite ends of its base line5 anchored to the ends of the cross arm 4: by strings 6 which are knotted and slipped through slots 7 in the ends of the cross arm as shown in Figure 3; Along its median time the head sail 1 is glued to the midrib 3 so that the apex of the triangle 1 extends adjacent one end of the midrib.

From the middle of the cross arm 4 a guy string 8 is stretched to the end of the midrib where it is engaged in a slot 9, a knot in the end portion of the string serving to hold it in tension. From opposite ends of the cross arm 4-. guy strings 10 extend to the other end of the midrib 3 and preferably, these strings 10 are integral, with a knot tied at the middle of the length of the string where it will normally engage in the slot 11 in the end of the midrib 3. A hole 12 is bored into the-stick in the end to form an enlarged recess or pocket in the slot 11 to receive the knot and ordinarily this positioning of the knot will hold the parts in proper balance; but if this should 1926. Serial No. 123,118.

prove not to be the case the knot in the string 10 may be shifted to one side or the other of the midrib 3 so as to alter the tension in the two halves of the string to compensate for any inequality of the other parts. It will thus be seen that the cross arm t is held by the tension of the guy string 8 and theguy strings 10, but is not itself actually attached to the midrib 3, and within a limited rang-e may shift across the midrib in response to wind pressure on the main sail. The main sail 2 is approximately of the form of an isosceles triangle, but

to give the sail the desired fullness so that it may pocket the wind to a certain extent the baseline of the triangle is not perfectly straight but is cut as indicated by the dotted line 13 in Figure 1. The sail 2 is then' socured to the cross arm. 4 by gluing this base edge to the cross arm and is held in position on the kite frame by a short string 1 1 extending from the apex of the sail through a cross slot '15 in the same end of the midrib 3 in which the guy strings 10 are fastened. The sides of the main sail 2 also deviate from the outline of'a true triangle at the points 13- whereby they are given some added length which allows of the curving of the sail away from a true plane;

The triangular go-re- 16 is cut out of the sail 2 at the ,middle of its base line leaving a portion of the midrib exposed so that one branch 17 of the divided leading string may pass through this gore of the sail for attachment to the midrib 3. The other branch 18 of the leading string is anchored in the slot 9 at the'head end of the midrib.

Viewed from the underside of the kite the main sail are in balance,carryingthe cross arm 2 with them in this lateral adjustment. The construction described permits the kite to be quickly knocked down for shipment main sail 2 is pressed upwardly against the 1 or storage as each of the strings engaging the slotted ends-oi? the two sticks "is simply held in place by thet'ension of the assembly,

string 18 front said slot so that it be drawn through; the gore 1O ciear of the sail 2 and its cross arm 4. The Various ony strings are easily Wrappedaho'iitthe sticks so that the whole kiteinay be contained in'a package whose Jengti' is "thatfof menial; t rib {3 andWhoseidiaineter isonly one "or two inches.

WVhen the kite has been lre-asseinhled and 7 tested inflight itanaylbednecessary to rnake T I a slight adj nstment in theknot'of ;the' string 10. If the kite tends to fly orftiltitowal'd the right (as viewed not; head isail en'd) the center knot in the" g'n string 10 is lifted 0111; Or the hor yiat and 5 area" to the right side of the sIot'IlL If the'kite tilts toward 'theleft the stringis ladjiistld in the opposite direction Theslight change will'cem ensate for practically any in'etluality in the parts althonghit is obvious itanyj' reatjer alteration Wererequired" the knot itsl 'cofild be loosened and string 10.

shifted slight-1y along the 'fied form of theiiiventionf inaifhi'ch there-"ate r three headsails Q1 each similar inshape to thehead sail 1 "of Figural andstrranged in tandem upon an elon gatedmidrih 23. responding to "each head sail I provide a cross arin 24am steady these tress 'arlnsin position by extending the obliquekite strings 30 from the other-end ofthernidrib23to engage the endsfof all 'three cross'arlns 24. "I then connect the: upper-mostcros'sarm 24: "with the head end of the Inidrib 23'by oblique guy strings 31so thatthe crossarms are free to siipdaterally upon the midrib 23 as in the striictu're first described. The

single main sail QOis shown at thelo'vver or rear endof the midrib and s attachedto the nearest "crossfarin 24. The branches 37 'and38' of the leading string are attached in Figure 1 to the midrib respectively "adj acent to the main sail 20 and "thehase of *the topmost head sa'il 21; and it'ivill he understood that the position of'attachment; may bevaried according to the niiriiber of "sails employed.

' Obviously a kite ."of this construction Will have greater grilling power'than that shown iitthe principle by-which it The cross ar i'n isIWhOH'ydise proper-balance in the air is headset attached to the mid-rib, a main sail attached to :the crossarrn, ties connecting theopposite sides of the head sail to the opposite ends of the cross arm, guys extendingfrointhehnds'of the cross arm to one end of ,the lnidmib and means connecting the c mainsail ex'tendiizrg Under the Inid-rib,"b1lt being unconnected "thereto except at the end laterally under infihence of the "Wind,

4. In a kite a-S' defined m laimi, said main sail being-designed withdnllnesslongitudinally or the mid-'rib-s'o that in the wind wind at opposite sides "of "the t it bulges away fromthe planefformed b'y orces said sail r ainst the mid-ribwat its medizrlportion a w hile causing its edges "to' ibulge -away from 6. In a kiteFas definetl in elairn 1, the Cross arm' extending under the 1 m'id -riband "afbranc'hjed "leaderstring attached to the rnid-rihgat its forwardend and ate point the cross a'rinp i g a r itckit'e comprising a head Banana a main saily'ea ch in I the term of; 'iin isosceles triangle, ar'riid-rib and-a erons arm nnconnected atvtheir adjacent pot-titans with the "base or the 1 main sail atta'cheiil to the cross the and the head sailadherently attached points anchored to the en'ds of the cross afrnfandthe main sail having its vertex anchored to one 'en'd ofthe mid-rib. V 8. In afkitecomprisin twosails and two "frame sticks, said stic's being arranged transversely of each "other; but unconnected at their ad acent portions,-one-sail beingattaohed 4 to one' 'stick along -a line of snbsta-ni tial len'gth and having its corners opposite said line anchored to the ends of the other stic'k andtheot her sail b'eing attached-t0 said other stick along a *line; of substantial length with an opposite portion of the sail "connected to the first mentioned stick.

9. 'Inthe 'conflainzdziondefined in claim 7 said inain sail 'having a trian ular openin at its middle portion adjacent the base,=sai

opfning having a' vertex adjacent the midr1 10. In the combination defined in claim 7, said main sail having a triangular opening at its middle portion adjacent the base, said opening having a vertex adjacent the mid-rib, together with a branched leading string having one end attachedto the end of the mid-rib adjacent the vertex of the head sail and its other branch attached to the mid-rib extending through the opening in the main sail.

11. A kite comprising a mid-rib and a cross arm, a head sail presenting triangular areas to the wind, each attached to the'midrib along one side of the triangle, and having their opposite points attached to the cross arm with fullness between the points of attachment, and a triangular main sail secured to the cross arm along one side with its opposite corner attached to the mid-rib.

12. In the combination defined in claim 1, a hanger string connecting the middle of the cross arm to the otherend of the midrib opposing the stress of said guys.

13. A kite comprising a frame which consists of a mid-rib and a cross arm transversely disposed with respect to each other and unconnected at their adjacent portions a hanger string extending from one end of the mid-rib to the middle of the cross arm, and guy stringsv extending from the ends of the cross arm to the other end of the midrib, together with sails attached to the frame with fullness between their points of attachment, whereby the frame members and the sails can shift with respect to each other for balancing themselves under pressure of the wind.

lt. In a kite, a frame comprising a midrib and a cross arm attached thereto by means of a hanger string extending from one end of the mid-rib to the middle of the cross arm, and guy strings from the ends of the cross arm to the other end of the midrib, whereby the cross arm is adapted to shift laterally over the mid-rib, and a sail attached at one end to the cross arm, and at the other end to the mid-rib, with fullness in its lateral margins,the middle portion of the sail overlying the mid-rib, but adapted to shift thereon.

CONRAD DAHL. 

